St. Thomas Aquinas' definition of love is "to will the good of another" - is it same as defining love as "to desire the good of another"?
According to Aquinas, does "loving" always require "desire for the good of another"?
The answer is NO!
In Summa Theol., I-II, Q. xxiii, a. 4, St. Thomas Aquinas states that there are six passions for the concupiscible appetite: love and hatred, desire and aversion, joy and sadness; and five for the irascible appetite: hope and despair, courage, fear, and anger. [Cf. Appetite | New Advent].
Therefore according to St. Thomas Aquinas, love and desire both belong to the passions for the concupiscible appetite but he does not equate the two.
CCC 1765 teaches that love causes a desire for the absent good and the hope of obtaining it; this movement finds completion in the pleasure and joy of the good possessed.
My understanding is that love a passion causes desire another passion, only when the good willed is absent. Once the good is obtained, love continues but the desire now is fulfilled and complete and rests in the pleasure and joy of the good possessed [cf. heaven].